Such arrangements are known, for example, from EP 1 270 127 A1. They are used, for example, to remove burrs formed on the end peripheral areas of the tooth flanks in the machining of gear wheels (such as hobbing, for example). Burrs must be removed for several reasons. One of the reasons is that in the subsequent work steps, an end face of the gear wheel is often used as a planar inside recess and determination surface, and the burr interferes with said planarity. Furthermore, after hardening, the burr would create the risk of breaking off later on when the gear wheel runs in a transmission, thus causing damage to the tooth flanks or to components of the transmission. Aside from that, this type of burr also represents a risk of injury during the handling of the work piece wheels, and it is not sufficient to merely remove the burr because the remaining tooth edge can be come glass-hard during hardening due to over-carburization, and then chip under pressure.
To avoid these disadvantages, the end peripheral areas of the tooth flanks are machined with a tool wheel mentioned above to transform the tooth edge into a chamfer. To that end, the tool wheel is firmly clamped into a tool holding fixture, with the axes of rotation of tool wheel and tool holding fixture coinciding, and the tool wheel rotationally meshes with the work piece wheel to be machined. The required rotary actuating force is transmitted from a tool spindle to the tool wheel via the tool holding fixture. Machining processes such as deburring, forming the chamfer, or smoothing the end peripheral areas of the tooth flanks of the work piece wheel can be performed.
For example, a tool wheel suitable for this purpose is formed by two machining deburring wheels, which are mounted into a compact tool wheel with a spacer inserted between said deburring wheels. Instead of the spacer, it is also possible to use an end-cut guide wheel. Because secondary burrs are raised in the peripheral areas of the tooth flanks that border the chamfers when the tooth edges are reworked into the chamfers, it is advantageous to develop the guide wheel as a smoothing wheel over part of its circumference to smooth the secondary burrs, as was done, for example, in EP 1 270 127 A1.
The form of the toothing of the tool wheel is adapted to the toothing of the work piece wheel. In particular, with helical gearing, the helix angles are adapted. More specifically, to obtain an optimal machining result, the tool wheel must be adapted precisely to the correction values of the work piece. Otherwise, material raised on the tooth flanks of the work piece may lead to premature tool wear during the subsequent hard metal cutting of the work piece.
However, the correction values of the work piece wheels are already subject to change due to process tolerances in the hobbing of the work piece wheels, depending on the batch, and thus the precise adjustment of a tool wheel to various batches of otherwise equal work piece wheels is no longer a given. The same applies if the correction values must be changed in view of the subsequent hardening of the work piece wheels due to different materials or different hardening furnaces.
Simply put, when the gear cutting parameters of the work piece wheels change even very slightly, the tool wheel no longer fits precisely enough for the machining of the work piece wheels. When a tool wheel is developed in one piece, this only leaves the regrinding of the toothing of the tool wheel when machining several different batches of tool wheels.
To avoid this costly process, EP 1 270 127 A1 proposes to split the tool wheel in the center so that the tool wheel halves for the machining of opposite end faces of the work piece wheels can be twisted relative to each other and arranged with a randomly selectable circumferential positioning relative to each other. With a suitable arrangement, the tool wheel can then be precisely adjusted for each individual batch. However, this adjustment requires a lot of time and effort because it must be very precise.
Because of the aforementioned problems with the prior art, the object of the invention is to improve an arrangement described above, in particular with respect to an optimally simple adjustment of the tool wheel relative to the work piece wheel to be machined.
An object of the invention is attained with a modification of the aforementioned arrangement, which is essentially characterized in that the arrangement has an elastic means with a restoring force against which the direction of the axis of rotation of the tool wheel can be displaced relative to the direction of the axis of rotation of the tool holding fixture.